1. Field of the Invention
The present invention relates generally to vehicle service stands. More particularly, the present invention relates to portable, user configurable service stands suitable for maintenancing relatively heavy and large riding lawnmowers and similar motorized devices.
2. Description of the Related Art
Riding lawn mowers, also known as “sit down” mowers, have become increasingly popular over the years. Typical riding mowers are much more powerful than “walk behind” mowers, and they usually include larger blades or arrays of blades. Riding mowers have the advantage of speed and comfort, and especially where large acreages need regular mowing, they are extremely worthwhile tools. Modern riding mowers are not limited to mowing; often additional mechanical accessories are available to adapt such mowers for other jobs like leaf gathering or mulching. Furthermore, late model riding mowers are sufficiently powered to tow moderately loaded trailers or other wheeled yard implements. Experienced owners soon find applications other than mowing, so modern riding mowers may be put to substantial uses year round.
While the cutting of lawn grass is much easier and faster with modern riding mowers, and the numerous other advantages and applications of such mowers are not in doubt, periodic maintenance is a vital necessity. Because of the complexity, size and weight of typical modern riding mowers, and the often harsh conditions of use, prudence dictates regular service. It is usually left up to the owner to maintain the mower, and typical owners soon run into many problems of lawn mower maintenance.
One frequent problem relates to under-deck grass build up. When moist grass is encountered, the caking and build-up of grass cuttings can be extreme. As a result, the exit path of the lower mower deck can become blocked. This will cause uneven spreading of the cut grass on a lawn Cleaning of the under deck should be performed many times during the mowing season. Mower blades need to be sharpened or replaced periodically for efficient use. Where V-belts are used to turn the blades, or the blade array, proper belt tensioning is desirable, and occasionally belt replacement is advisable. Of course, the mower engine needs regular service as well-obviously, the oil and oil filter must be changed regularly depending upon the frequency and intensity of mower use. In addition, wheel bearings must often be greased and sometimes replaced, ad other mechanical parts should be periodically lubricated.
It is often difficult to access mechanical regions of the mower requiring service. One problem with riding mowers is the mower deck can usually only be raised four to five inches off the ground. Without unobstructed access to the mower underside, work on the mower deck is difficult to perform. Parts such as blades can be difficult if not impossible to reach, without adequate clearance. Dangers of hand injuries from sharp mower blades is a factor. Even the simple cleaning of the deck underside can result in a time consuming struggle without adequate ground clearance.
Thus, it has been recognized that with a mower disposed a comfortable distance above the ground, service and repairs are made easier and quicker. Many approaches have been taken in the past for manipulating mowers (or analogous devices) for service.
Some designs elevate the mower with a vertically displaceable platform that must be forcibly elevated into position. For example, U.S. Pat. No. 4,958,804 issued to Lenius, et al. Sep. 25, 1990 discloses a lawn mower lift comprising a supporting frame pivoted between raised and lowered positions relative to a lower base frame by a parallelogram linkage. A stop rail maintains the support frame in the raised position by abutting the parallelogram linkage in an overcenter position. The supporting frame lies between parallel side rails of the base frame, which serve as a guide track to properly align a mower on the supporting frame.
Another lifting platform is seen in U.S. Pat. No. 5,339,926 issued to McCanse , et al. on Aug. 23, 1994. A carriage raises mowers or garden tractors to expose their underside for servicing. The vertically movable carriage has two cantilevered lift forks, which may be adjusted along the carriage to accommodate the longitudinal wheelbase of the vehicle. Each lift fork carries two adjustable cups for cradling and supporting vehicle wheels. The cups extend away from the forks to allow free access to crucial components of the vehicle.
U.S. Pat. No. 6,474,626 issued to Box on Nov. 5, 2002 discloses another rack that vertically elevates a mower above ground for service. A base for resting on a support surface supports first and second spaced apart rails to receive wheels of a lawn mower. A first lifter elevationally supports rearward portions of the longitudinal rails above the base, and a second manually operated lifter, independent of the first lifter, elevationally supports forward portions of the rails. Thus, only approximately one half of the weight of a lawn mower need be lifted at a time.
U.S. Pat. No. 6,675,847 issued to Noden on Jan. 13, 2004 discloses an adjustable height workbench. Twin standards, each with a pawl mechanism, provide height adjustments by extending rods that engage ratchet apertures. A safety mechanism prevents inadvertent disengagement of the rod from the ratchet apertures. A tension spring connected between a chain and a foot actuator pedal prevents accidental release of the rod by absorbing unintentional or inadvertent forces applied to the pedal.
Recognized problems with lifting platforms, i.e., ramps or stands employing mechanically driven elevators, include complexity, required strength, and cost. Where self propelled devices such as riding lawnmowers, ATV's, snowmobiles or the like are to be serviced, it is advantageous to elevate these devices using their own power. With ramps lacking driven elevators, there are fewer moving parts, and an element of simplicity is achieved. Further, non-motorized lifts are more reliable, they are more stable, and the likelihood of injury or component breakdown is reduced. When properly designed and deployed, passive service ramps are safer than motorized versions, and they are more cost effective. Without motorized lifting parts, a given cost of material and parts results in a stronger design.
Rather than use powered elevators, some prior art designs merely tilt the apparatus being serviced to expose the undercarriage. For example, U.S. Pat. No. 5,096,171 issued to Kendrick , et al. Mar. 17, 1992 discloses a lawn mower service stand for supporting either a walk-behind type mower or a tilted mower. A central pit for receiving an oil collecting tank receives drained engine oil. U.S. Pat. No. 5,632,475 issued to McCanse on May 27, 1997 discloses a work holding apparatus that is used to tilt heavier devices like mowers. A central lift is movable upwardly and downwardly on a column.
U.S. Pat. No. 5,678,804 issued to Lintelman, et al. Oct. 21, 1997 discloses another tilting device. A mobile jacking device can be wheeled into place for engaging and then tilting a mower to expose the undersides for service. The jacking device comprises a wheeled axle, an extended vertical element secured to the axle, a support secured to the axle, and a gripping piece secured to an end of the support. Preferably, a foot assist bar is also secured to the extended vertical element to assist the lever element in raising the lawn mowing equipment.
Another tilting mechanism is seen in U.S. Pat. No. 6,139,247 issued to Wright Oct. 31, 2000. The transporting apparatus has a tiltable carrying rack hinged to a frame. The rack receives and supports the front of an ATV for towing it about. With the rack tilted, the underside of the vehicle supported by the rack is exposed for service.
U.S. Pat. No. 6,488,255 to Lowmaster issued Dec. 3, 2002 also discloses a tilting device exposing a lawnmower undercarriage for maintenance and/or repairs. It includes a stabilizer for insertion into the ground and a retainer connected to the stabilizer for holding the lawnmower handle adjacent the ground, thereby tilting the lawnmower relative to the ground such that the undercarriage is accessible.
U.S. Pat. No. 7,350,790 to Wilson issued Apr. 1, 2008 provides a tilting dolly for servicing snowmobiles or the like. The dolly engages the front bumper and raises the snowmobile. An auxiliary rear axle is then slid under a rear portion of the snowmobile. A swivel connection on the front bumper-engaging member allows the snowmobile supported by the dolly to be easily maneuvered in tight spaces. The dolly may be reconfigured for use as a jack stand allowing service or repair work to be performed. The dolly is adapted to be towed behind a riding lawnmower, yard tractor, or the like, further enhancing the utility of the dolly.
U.S. Patent Application No. 20080156589 published Jul. 3, 2008 discloses a lifting platform suitable for riding lawn mowers. A load-bearing platform is operated by a lift mechanism. The platform has a number of decks associated with the platform and supported upon a chassis. The decks are movable, or optionally removable, and slide sideways on the chassis provide an adjustable surface support area.
However, tilting mechanisms offer an incomplete solution to the service problem. First, a heavy riding lawnmower that is tilted may be unstable, and repairs can be unsafe and dangerous. While elevated parts of the tilted device may be rendered accessible, the lower parts can remain partially hidden or even blocked. Some service adjustments are best made while the vehicle is level. For example, oil and oil filter changes are best made proximate a level surface, to avoid spillage and to maintain the elevation of the oil input path.